Bis(N,N',N''-triisopropyl-guanidinium) fumarate-fumaric acid (1/1)

The asymmetric unit of the title compound, C(10)H(24)N(3) (+)·0.5C(4)H(2)O(4) (2-)·0.5C(4)H(4)O(4), comprises a triisopropyl-guanidinium cation, half of a fumarate dianion and half of a fumaric acid mol-ecule; both the fumarate dianion and the fumaric acid mol-ecule are located on inversion centres. In the crystal, inter-molecular O-H⋯O hydrogen bonds between the carboxyl groups of the fumaric acid mol-ecules and the carboxyl-ate groups of the fumarate anions lead to the formation of a hydrogen-bonded supra-molecular twisted chain along the b axis. The triisopropyl-guanidinium cations inter-act with the fumarate-fumaric acid chains via extensive N-H⋯O and C-H⋯O hydrogen bonds, leading to a ladder arrangement, with the cation being the rungs that bridge three curled chains of fumarate-fumaric acid. The crystal packing is stabilized by N-H⋯O and C-H⋯O (cation⋯fumarate/fumaric) and O-H⋯O (fumarate⋯fumaric) hydrogen bonds, consolidating a three-dimensional network.